Apparatus for hydrocarbon operations and method of use

ABSTRACT

The present invention provides an apparatus for performing an operation in a fluid conduit of a hydrocarbon exploration or production installation and methods of use. The apparatus comprises a body configured to be received in a fluid conduit, which is coupled to a tool fluid conduit defining a flow bore. An imaging device is carried by the body and a flow direction arrangement provides a fluid circulation path between an annulus located between an interior wall of the fluid conduit and the body and the flow bore in use. The flow direction arrangement is configured to provide a deployment thrust on the body when fluid is circulated between the annulus and the flow bore through the fluid circulation path. Applications to the inspection of flexible risers and applications to the placement of a fluid or material a treatment operation are described.

The present invention relates to apparatus for use in fluid conduits inthe hydrocarbon exploration and production industry and methods of use,and in particular to methods of inspecting the interior of fluidconduits; placing treatment fluids in fluid conduits; and/or treatinghydrate deposits in fluid conduits. Aspects of the invention relation tofluid conduit operations in hydrocarbon exploration and productioninstallations in which the deployment of an apparatus is assisted by afluid circulation method, and preferred embodiments relate to a methodand apparatus for simultaneous inspection of a fluid conduit andplacement of a fluid to an inspection location. The invention hasparticular application to the internal inspection of flexible risersystems using fluid circulation for tool deployment and/or fluidplacement.

BACKGROUND TO THE INVENTION

Inspection of fluid conduit systems in hydrocarbon exploration andproduction installations is necessary in order to monitor theircondition and performance, and consequently a variety of internal andexternal inspection techniques are in common use and form part ofconduit inspection and monitoring regimes. Exterior inspectiontechniques can provide relatively easy access and application ofinspection equipment, but have limitations in their assessment ofstructural or internal conditions. Internal inspection enables a numberof internal and/or structural characteristics to be assessed, includingthe thickness of an internal wall, the presence of debris or scalewithin the conduit; the presence of interior corrosion; and/or anydamage or defects to the fluid conduit structure. However, internalinspection techniques present challenges to oil and gas operators andservice companies, including those associated with successful tooldeployment and robustness of the inspection tools in hostile conditions.

An exemplary application is the internal inspection of subsea pipelineand flexible riser production systems. FIG. 1 shows schematically asubsea production system, generally depicted at 100, at which a FloatingProduction Storage and Offloading vessel (FPSO) 102 is coupled to asubsea pipeline 104 via a pair of flexible risers 106 a, 106 b. Theflexible risers 106 are joined to the subsea pipeline 104 via SubseaIsolation Valves (SSIVs) 108 a, 108 b. The subsea pipeline 104 comprisesa pigging loop, which may be several kilometres in length. The pipelineis tied in to several subsea wells via manifolds 110. The flexiblerisers 106, shown here in lazy S wave configuration, are subject tostress and fatigue, and it is desirable to inspect the flexible risersregularly to ensure their integrity. However, external inspection offlexible riser is challenging due to the multi-layer structure of theriser carcass and the requirement for ROVs to provide deepwater access.It is also desirable to inspect the interior of the SSIV to establishthat it is in good condition and is functioning correctly.

A conventional internal inspection of the flexible riser system shown inFIG. 1 involves complete de-watering and de-oiling of the subseapipeline 104 and the flexible risers 106 to enable internal inspectiontools to be deployed. This necessitates the complete shutdown ofproduction. Clearly this has significant and undesirable economicalimplications for the operator of the production system.

It is known to use coiled tubing intervention to provide access topressurised wellbores, for example in wellbore cleanout and fluidplacement methods. Coiled tubing is a long continuous length of metalpiping wound on a spool, which is straightened by plastic deformationand inserted into the wellbore. In a cleaning application, fluid iscirculated through the inside of the coiled tubing and back out throughthe annulus between the coiled tubing and the wellbore. Particulatematter in the wellbore is brought to surface by the circulating fluid.When performing this type of wellbore operation, it is necessary toemploy procedures and equipment for controlling and retaining pressurein the wellbore system to ensure it is isolated from surface. A typicalpressure control system includes an injector head, which contains adrive mechanism to push and pull the coiled tubing in and out of thehole through a pressure control device.

The coiled tubing injector system described above is therefore asubstantial and heavy piece of equipment, with large footprint and highcapital expense. The coiled tubing injector system also requires adistance of several metres to be available above the isolation valve toaccommodate the injector and the gooseneck. This limits the number ofinstallations where coiled tubing operations can be performed and canmake operations more costly. These problems are particularly significantin the case of offshore operations, for example in a turret of afloating production storage production and offloading vessel (FPSO)where space is at a premium and cranes are unable to lift the componentsinto place. Even light coiled tubing units which are used onshore arestill substantial pieces of equipment which are large in size and weightin the context of offshore operations.

To alleviate the problems associated with coiled tubing injection suchas helical lock-up, coiled tubing thruster systems have been developed.Examples are described in US 2005/247448 and US 2011/277255. The systemsuse thruster pigs on the end of the coiled tubing to create anadditional force on the coiled tubing which enables it to be deployed togreater depth. Fluid is pumped down the annulus between the wellborewall and the coiled tubing, and applies pressure against the thrusterpig, before the fluid passes out of in front of the bottomhole assembly.The fluid then returns to surface through the bore of the coiled tubing.

WO2006/001707 and US2005/0284504 also describe thruster pig systems forhydrate removal which include return flow lines.

Other considerations limit the applications of coiled tubing. Firstly,blockages and restrictions can occur in narrow bore fluid conduits,which are simply too small to receive coiled tubing. In addition, thecoiled tubing injector systems described above rely on the rigidity ofthe coiled tubing to allow it to be pushed into a hole, rather thanrelying on gravity only (as is the case in wireline operations).However, this rigidity also has drawbacks that make coiled tubinginterventions unsuitable for some applications. For example, it may notbe possible to inject coiled tubing into a fluid conduit which has adeviated or convoluted path. In extreme cases, the rigid coiled tubingmay not be able to pass through some curved or bent pipeline systems.Even where passage is possible, the frictional resistance between thecoiled tubing and the inside wall of the wellbore will limit the depthto which the coiled tubing can be deployed.

Furthermore, the systems described in US 2005/247448, US 2011/277255,WO2006/001707 and US2005/0284504 are not concerned with inspectionmethodologies.

It is amongst the objects of the invention to provide an apparatus forperforming operations in fluid conduits of hydrocarbon exploration orproduction installations which mitigates or obviates the drawbacks ofcurrently available apparatus. It is an object of at least one aspect ofthe invention to provide a method of inspecting the interior of a fluidconduit which is improved with respect to previously proposed inspectionmethods. It is an aim of an aspect of the invention to provide animproved method and apparatus for placing a fluid at an interior of afluid conduit.

A further aim of an aspect of the invention is to provide a method andapparatus for deploying an inspection tool in a fluid conduit, whichdoes not necessitate de-watering or de-oiling the fluid conduit.

Further aims and objects of the invention will become apparent from thefollowing description.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided anapparatus for performing an operation in a fluid conduit of ahydrocarbon exploration or production installation, the apparatuscomprising:

a body configured to be received in the fluid conduit and coupled to atool fluid conduit defining a flow bore;an imaging device carried by the body; anda flow direction arrangement configured to provide a fluid circulationpath between an annulus located between an interior wall of the fluidconduit and the body and the flow bore in use;wherein the flow direction arrangement is configured to provide adeployment thrust on the body when fluid is circulated between theannulus and the flow bore through the fluid circulation path.

The apparatus may be configured as an inspection apparatus.Alternatively or in addition the apparatus may be configured as a fluidplacement apparatus or a cleaning apparatus.

According to a second aspect of the invention, there is provided amethod of inspecting the interior of a fluid conduit in a hydrocarbonexploration or production installation, the method comprising:

providing an inspection apparatus in the fluid conduit to be inspected,the apparatus comprising: a body coupled to a tool fluid conduitdefining a flow bore; an imaging device carried by the body; and a flowdirection arrangement disposed between an exterior of the body and theflow bore;circulating fluid between an annulus between an interior wall of thefluid conduit and the tool fluid conduit and the flow bore, through afluid circulation path defined by the flow direction arrangement;deploying the apparatus along the fluid conduit by a thrust on theapparatus resulting from the circulation of fluid between the annulusand the flow bore through the fluid circulation path;imaging the fluid conduit using the imaging device; andcapturing, analysing and/or displaying imaging data.

The fluid conduit may comprise a flexible riser, and therefore themethod may comprise a method of inspecting the interior of a flexibleriser.

Embodiments of the second aspect of the invention may comprise featuresof the first aspect of the invention and its embodiments or vice versa.

According to a third aspect of the invention, there is provided a methodof placing a treatment material at an interior of a fluid conduit in ahydrocarbon exploration or production installation, the methodcomprising:

providing a material placement apparatus in the fluid conduit, theapparatus comprising: a body coupled to a tool fluid conduit defining aflow bore; an imaging device carried by the body; and a flow directionarrangement disposed between an exterior of the body and the flow bore;circulating fluid between an annulus between an interior wall of thefluid conduit and the tool fluid conduit and the flow bore, through afluid circulation path defined by the flow direction arrangement;deploying the apparatus along the fluid conduit to a location displacedfrom the entry point to the fluid conduit, by a thrust on the apparatusresulting from the circulation of fluid between the annulus and the flowbore through the fluid circulation path;placing a treatment material at the displaced location;imaging the interior of the fluid conduit using the imaging device; andcapturing, analysing and/or displaying imaging data.

The method may further comprise at least one of storing, analysing ordisplaying the imaging data.

The treatment fluid comprises a blockage removal treatment fluid. In oneembodiment, the displaced location is the location of a hydrate depositin the fluid conduit, and the method may comprise removing at least apart of the hydrate deposit.

The method may further comprise monitoring the effect of the treatmentfluid on the hydrate deposit using the imaging device to acquire imagingdata, and/or may comprise advancing the apparatus towards the hydratedeposit for further fluid treatment.

Embodiments of the third aspect of the invention may comprise featuresof the first or second aspects of the invention and their embodiments orvice versa.

According to a fourth aspect of the invention, there is provided amethod of treating a hydrate deposit at an interior of a fluid conduitin a hydrocarbon exploration or production installation, the methodcomprising:

providing a fluid placement apparatus in the fluid conduit, theapparatus comprising: a body coupled to a tool fluid conduit defining aflow bore; an imaging device carried by the body; and a flow directionarrangement disposed between an exterior of the body and the flow bore;circulating fluid between an annulus between an interior wall of thefluid conduit and the tool fluid conduit and the flow bore, through afluid circulation path defined by the flow direction arrangement;deploying the apparatus along the fluid conduit to a location on oneside of a hydrate deposit in the fluid conduit, by a thrust on theapparatus resulting from the circulation of fluid between the annulusand the flow bore through the fluid circulation path;placing a treatment fluid at the location of the hydrate deposit; andmonitoring the effect of the treatment fluid on the hydrate depositusing the imaging device to acquire imaging data.

The method may further comprise at least one of storing, analysing ordisplaying the imaging data.

The method may further comprising removing a part of the hydratedeposit, and may comprise advancing the apparatus towards the hydratedeposit for further fluid treatment.

Embodiments of the fourth aspect of the invention may comprise featuresof the first to third aspects of the invention and their embodiments orvice versa.

According to a fifth aspect of the invention, there is provided a methodof deploying an inspection apparatus in a fluid conduit in a hydrocarbonexploration or production installation, the method comprising:

providing an inspection apparatus in the fluid conduit to be inspected,the apparatus comprising: a body coupled to a tool fluid conduitdefining a flow bore; an imaging device carried by the body; and a flowdirection arrangement disposed between an exterior of the body and theflow bore;circulating fluid between an annulus between an interior wall of thefluid conduit and the tool fluid conduit and the flow bore, through afluid circulation path defined by the flow direction arrangement; anddeploying the apparatus along the fluid conduit by a thrust on theapparatus resulting from the circulation of fluid between the annulusand the flow bore through the fluid circulation path.

Embodiments of the fifth aspect of the invention may comprise featuresof the first to fourth aspects of the invention and their embodiments orvice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

There will now be described, by way of example only, various embodimentsof the invention with reference to the drawings, of which:

FIG. 1 is a schematic representation of a conventional subsea productionsystem comprising a pigging loop and a pair of flexible risers;

FIG. 2 is a schematic representation of a system according to anembodiment of the invention;

FIG. 3 is a schematic representation of an a bottomhole assembly of theembodiment of FIG. 2, shown in longitudinal section in a fluid conduit;

FIGS. 4A, 4B and 4C are respectively sectional views of umbilicals whichmay be used with the present invention;

FIG. 5 is a schematic representation of an example application of thepresent invention in a method of inspecting a flexible riser;

FIGS. 6A to 6D are schematic representations of sequential steps in anexample application of the present invention to a method of treating ahydrate in a fluid conduit;

FIGS. 7A to 7C are schematic representations of sequential steps in anexample application of the present invention in a method of delivering atreatment fluid to a leak location in a fluid conduit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As noted above, FIG. 1 is a schematic representation of a typical subseaproduction system comprising a pigging loop and a pair of flexiblerisers according to the prior art. It is an aim of present invention toenable internal inspection of the flexible risers 106 and/or at leastthe riser side of the SSIVs 108 which is improved with respect to thede-watering and de-oiling methods performed conventionally.

Referring now to FIG. 2, there is shown a system according to anembodiment of the invention, generally depicted at 200. The system 200comprises an apparatus 300 (shown in more detail in FIG. 3) formed froma bottomhole assembly 302 and a tool fluid conduit 304, which in thiscase is a flexible umbilical. The apparatus 300 is shown here in situ ina fluid conduit 202, which in this case is a flexible riser. Theapparatus 300 is deployed from a storage reel 204 via an injector unit206 and a stripper and blow out preventer (BOP) unit 208.

The injector unit 206 comprises a drive mechanism for pushing and/orpulling the umbilical into and out of the fluid conduit through thepressure control apparatus. The drive mechanism comprises an arrangementof blocks shaped and sized to engage with the outer surface of theumbilical by forming an indentation in the outer surface to a depth of 1mm or less. This sufficient engagement with the umbilical to inject orretract it, but does not penetrate the outer wall of the umbilical.

The stripper comprises internal pack off elements formed from anelastomeric material, arranged to provide a fluid seal with the outersurface of an umbilical passing through the unit. The stripper 36 allowsthe umbilical to pass through the apparatus while retaining pressure inthe conduit system beneath the stripper.

The blowout preventer comprises a shear and seal blowout preventer,which has the capability to cut or otherwise sever an umbilicalintroduced to the fluid conduit. This embodiment also comprises achamber which functions as a lubricator, providing an access point forthe coupling of the bottomhole assembly to the umbilical. A divertor(not shown) is also provided to create a fluid inlet for fluid pumpedinto the annulus between the introduced umbilical and the inner surfaceof the fluid conduit 202.

A control module 210 communicates with the other elements if the systemto control its operation and receive data collected from the apparatus200.

FIG. 3 shows the apparatus 300 in more detail. The bottomhole assembly302 comprises a body 306 coupled to the flexible umbilical 304, and thebody defines a throughbore 308 from a leading end 310 of the bottomholeassembly to a trailing end 312 joined to the umbilical 304. Thethroughbore 308 is continuous with the flow bore 316 of the fluidumbilical 304 and therefore there is a flow path through the bottomholeassembly to the umbilical and to surface.

The body 306 supports an imaging device selected for internal conduituse. The imaging device 314 must be capable of withstanding the hostileconditions (including impact forces, pressure, temperatures, andexposure to corrosive fluids) of the interior of the fluid conduit, andmust be sufficiently small and lightweight for remote deployment. Theimaging device must also be capable of collecting and storing ortransmitting imaging data of sufficient quality and suitability for theapplications envisaged.

In a preferred embodiment of the invention, the imaging device is anoptical camera 314, provided with a data transmission cable 318 whichpasses through the bottomhole assembly to the umbilical, for thetransmission of real-time images to the control module 210. In thisembodiment, the camera comprises a fishbowl-type lens with a large fieldof view around the circumference of the conduit, with digital control toenable the selection of a section of the image received for additionalattention and/or image collection. The imaging device is thereforecapable of imaging the entire length of the conduit in a single pass. Asuitable choice of imaging device is the Vision ReadyCAM™ camera systemavailable from VisionIO AS of Sandnes, Norway although alternativeembodiments may use other imaging devices.

The bottomhole assembly 302 also comprises a flow direction arrangement320, supported by the body 306, which provides a fluid circulation pathbetween the annulus 324 located between an interior wall of the fluidconduit and the body and the throughbore. In this embodiment, the flowdirection arrangement defines a convoluted fluid path for fluid passingdown through the annulus to the bottomhole assembly 302, and out throughan outlet 322 at the leading end 310. As the fluid passes through theflow direction arrangement 320, a thrust force is generated on thebottomhole assembly to deploy it into the fluid conduit 202. Themagnitude of the thrust force is controlled by the pressure of fluidpumped down in the annulus from surface. The design of the flowdirection arrangement 320 is in this embodiment in accordance with theprinciples described in US 2005/247448 and US 2011/277255 (the contentsof which are incorporated into this specification by reference), withsuitable modifications to accommodate the mounting of the imaging device314 and the routing of the cable 318 through or past the bottomholeassembly to the umbilical 304. In addition, in embodiments of thepresent invention the bottomhole assembly need not create a seal withthe interior of the conduit in order to generate sufficient thrust todeploy the apparatus (which is lighter than the coiled tubing systemsdescribed in US 2005/247448 and US 2011/277255.

FIGS. 4A, 4B and 4C are respectively cross-sectional views throughflexible umbilicals according to exemplary embodiments of the invention.Referring firstly to FIG. 4A, the umbilical, generally shown at 400,defines a flow path for return fluids from the bottomhole assembly andcomprises the cables and conductors between the surface and thebottomhole assembly (in particular the imaging device 314). Theumbilical 400 defines an internal flow bore 402 for the return fluidsand has a multiple layer wall 404. The wall 404 includes an outerpolymer coating layer 406, formed from polyamide and/or polyurethanematerial, and a fibre-reinforced (e.g. KEVLAR™) braiding layer 408 toprovide tensile strength and sidewall compression protection. A resinfiller layer 410 surrounds the cables 414, which are wires, conductors,fibre optic cables, or combinations thereof. In this case the cables 414are arranged rotationally symmetrically around the internal flow bore.Together they function to enable transmission of data from thebottomhole assembly (including data captured by the imaging device) andtransmission of control signals from surface to the apparatus andimaging device.

The overall outer diameter is selected to be around 1½ inches (37 mm) orless to facilitate a range of fluid conduit applications and storage ofsignificant lengths (e.g. greater than 500 m) of the umbilical on arelatively lightweight and compact storage reel. The minimum bend radiusof the umbilical is selected to be less than 40 times the inner diameterof the tubing, and in a preferred embodiment the hose has a minimumelastic bend radius of approximately 12 times the inner diameter of thetubing (i.e. about 450 mm for a 37 mm hose). The flexibility of the hoseis a clear distinction from coiled tubing applications. Typically steelcoiled tubing has a minimum elastic bending radius of around 200 timesthe inner diameter of the tubing.

Referring now to FIG. 4B, an alternative umbilical is shown, generallydepicted at 401. The umbilical 401 is similar to the umbilical 400 andwill be understood from FIG. 4A and the accompanying description, withlike features given like reference numerals. However, in the umbilical401, the cables 414 (which are wires, conductors, fibre optic cables, orcombinations thereof) are grouped together in the resin filler layer,such that the internal flow bore is not concentric in the umbilical.This allows a larger internal flow bore to be accommodated in anumbilical with the same outer diameter.

Referring now to FIG. 4C, an alternative umbilical is shown, generallydepicted at 420. The umbilical 420 is similar to the umbilical 400 andwill be understood from FIG. 4A and the accompanying description, withlike features given like reference numerals. However, in the umbilical420, the cables 424 are not grouped together in a resin filler layer.Instead they run along the interior flow bore 402 defined by themultiple layer wall 404. In this embodiment, the cables 424 aredecoupled from the wall and therefore are not subject to stresses due tothe pressure control equipment.

There will now be described some exemplary applications of the apparatusand systems described above to illustrate the unexpected advantages ofthe invention. Referring firstly to FIG. 5, there is shown schematicallya subsea production system, generally depicted at 500, at which aFloating Production Storage and Offloading vessel (FPSO) 502 is coupledto a subsea pipeline 504 via a pair of flexible risers 506 a, 506 b. Theflexible risers 106 are joined to the subsea pipeline 504 via SubseaIsolation Valves (SSIVs) 508 a, 508 b. The subsea pipeline 504 comprisesa pigging loop (not shown), which may be several kilometres in length.

The system 200 is deployed on the FPSO and includes the apparatus 300comprising the bottomhole assembly 302 and the umbilical 304. The SSIV508 a of the flexible riser 506 a is closed to isolate the riser 506 afrom the pipeline 504. Production flow is diverted through the SSIV 508b and the riser 506 b to the FPSO. With the riser 506 a containingproduction fluids, the system 200 is coupled to the riser, and theapparatus 300 is conveyed along the riser by pumping fluid down theannulus 510 and through the flow direction arrangement 320 of thebottomhole assembly 302 to generate a deployment thrust. Return fluidspass through the bottomhole assembly and into the flow bore of theumbilical. As the bottomhole assembly is deployed in the riser, theimaging device 314 captures imaging data from the interior of the riserand transmits them to surface via the umbilical 304 for display inreal-time, storage and/or analysis. The apparatus is able to inspect theriser all the way to the SSIV, and is also able to assess the conditionof the SSIV on the riser side.

Significantly, in the above-described method the flexible riser isinspected while production fluids are present in the riser, obviatingthe need for a time-consuming and expensive de-watering and de-oilingprocess. In addition, the inspection of the riser 506 a can take placewhile production fluids are flowing through the riser 506 b, avoidingthe need to shut down production. The process may be repeated for theother riser, with production fluid flowing in riser 506 b.

Referring now to FIGS. 6A to 6D, there is shown schematically the stepsof a method for treating a hydrate build up in a fluid conduit. TheFigures show the apparatus 300, including bottomhole assembly 302 andumbilical 304 in a fluid conduit 600. The presence of a blockage 602 hasbeen identified, and the apparatus 300 is conveyed to the blockagelocation from surface by circulation of a deployment fluid (not shown)in the manner described above with respect to the previous embodiments(FIG. 6A). At the blockage location the apparatus collects imaging datausing the camera 314 and transmits it to surface for display inreal-time to an operator. The operator may be able to determine thenature of the blockage from the imaging data, for example bydistinguishing between the presence of a hydrate and a malfunctioningvalve or collapse of a hose or jumper conduit. In some cases the natureof the blockage may already have been determined or inferred, in whichcase the details of the blockage may be verified. In either case, datarelating to the position and/or nature of the blockage can be collectedand recorded. In this case, the blockage is determined (or inferred) tobe a hydrate blockage.

With the bottomhole assembly in the desired location and at the desireddistance from the hydrate build-up, a treatment fluid is pumped fromsurface down the annulus 610 to the bottomhole assembly, where it passesthrough the bottomhole assembly to the surface of the hydrate (FIG. 6B).The fluid may for example be ethylene glycol (MEG), methanol, or water,and may be heated. The effect of the treatment fluid on the hydratebuild-up can be monitored by the imaging device to collect data relatingto its removal, and to control the treatment process. For example, theparameters of the delivery of the treatment fluid can be modified inresponse to the imaging data to enable the process to be carefullycontrolled. As the hydrate build-up is released, fluid is returnedthrough the apparatus to surface, and the apparatus is controllablyadvanced towards to the leading surface of the hydrate to maintain thedesired distance (FIG. 6C).

When the hydrate build up has been removed, as verified by the imagingdata from the apparatus, the apparatus is used to inspect the interiorof the fluid conduit to identify potential causes of the hydratebuild-up (FIG. 6D) before retrieval of the apparatus. Referring now toFIGS. 7A to 7C, there is shown schematically the steps of a method fortreating a fluid conduit leak. The Figures show the apparatus 300,including bottomhole assembly 302 and umbilical 304 in a fluid conduit700. The presence of a leak 702 has been identified, and the apparatus300 is conveyed to the blockage location from surface by circulation ofa deployment fluid (not shown) in the manner described above withrespect to the previous embodiments (FIG. 7A). At the leak location theapparatus collects imaging data using the camera 314 and transmits it tosurface for display in real-time to an operator. The operator may beable to determine the nature of the leak from the imaging data, forexample by providing information about size or shape of the leak. Insome cases the nature of the leak may already have been determined orinferred by other means, in which case the details of the leak may beverified. In either case, data relating to the position and/or nature ofthe leak can be collected and recorded.

With the bottomhole assembly in the desired location and at the desireddistance from the leak, a sealant material is pumped from surface downthe annulus 710 to the bottomhole assembly, where it passes through thebottomhole assembly to the surface of the hydrate (FIG. 7B). The sealantmaterial may for example be a leak sealing fluid or gel, or may compriseparticulate matter or a suspension thereof. Suitable sealant materialsare known in the art, and include without limitation pressure activatedsealant systems that use differential pressure across a leak site tocause liquid sealant to cause liquid sealant to polymerize into aflexible solid. Examples are available from Seal-Tite International ofLouisiana, US and are described in SPE 91400 “Internal Repair ofPipeline Leaks Using Pressure-Activated Sealant, David W. Rusch, 1994.

The effect of the sealant on the leak can be monitored by the imagingdevice to collect data relating to its removal, and to control thetreatment process. For example, the parameters of the delivery of thesealant can be modified in response to the imaging data to enable theprocess to be carefully controlled. As the leak is sealed, fluid and/orsealant is returned through the apparatus to surface, and the positionof the apparatus relative to the leak may be controlled. When the leakhas been sealed, as verified by the imaging data from the apparatus, theapparatus is used to inspect the interior of the fluid conduit toidentify potential causes of leaks or damage to the interior of theconduit (FIG. 7C) before retrieval of the apparatus.

The applications described with reference to FIGS. 6 and 7 above sharethe principle of deploying an apparatus to a location in a fluid conduitusing a fluid circulation mechanism to produce a thrust on theapparatus; using the fluid circulation mechanism in a second mode toplace a material at the location; and using an imaging device carried bythe apparatus to assist in the performance and/or verification of theoperation. Other applications (not illustrated) are also within thescope of the invention. For example, the apparatus may be used toidentify and/or locate the presence of debris in a fluid conduit, forexample a build up of residue at the low point of a mid-water arch in aflexible riser. The debris can then be circulated out of the flexibleriser using the apparatus, while the process is monitored. Its removalmay then be verified by the imaging device, and the conduit may beinspected for lasting damage.

The present invention provides an apparatus for performing an operationin a fluid conduit of a hydrocarbon exploration or productioninstallation and methods of use. The apparatus comprises a bodyconfigured to be received in a fluid conduit, which is coupled to a toolfluid conduit defining a flow bore. An imaging device is carried by thebody and a flow direction arrangement provides a fluid circulation pathbetween an annulus located between an interior wall of the fluid conduitand the body and the flow bore in use. The flow direction arrangement isconfigured to provide a deployment thrust on the body when fluid iscirculated between the annulus and the flow bore through the fluidcirculation path. Applications to the inspection of flexible risers andapplications to the placement of a fluid or material a treatmentoperation are described.

Modifications to the embodiments described above are within the scope ofthe invention and the invention extends to combinations of featuresother than those expressly claimed herein.

1. An apparatus for performing an operation in a fluid conduit of ahydrocarbon exploration or production installation, the apparatuscomprising: a body configured to be received in the fluid conduit andcoupled to a tool fluid conduit defining a flow bore; an imaging devicecarried by the body; and a flow direction arrangement configured toprovide a fluid circulation path between an annulus located between aninterior wall of the fluid conduit and the body and the flow bore inuse; wherein the flow direction arrangement is configured to provide adeployment thrust on the body when fluid is circulated between theannulus and the flow bore through the fluid circulation path.
 2. Theapparatus according to claim 1 wherein the body is configured to becoupled to a flexible umbilical.
 3. The apparatus according to claim 1wherein the imaging device comprises an optical camera.
 4. The apparatusaccording to claim 1 wherein the flow direction arrangement comprises aconvoluted fluid path for fluid passing between the annulus and the flowbore of the tool fluid conduit.
 5. A system for performing an operationin a fluid conduit of a hydrocarbon exploration or productioninstallation, the system comprising: the apparatus according to claim 1;and a tool fluid conduit defining a flow bore.
 6. The system accordingto claim 5 wherein the tool fluid conduit comprises a flexibleumbilical.
 7. The system according to claim 6 wherein the flexibleumbilical has an inner diameter and the minimum bend radius of theumbilical is less than forty times the inner diameter.
 8. The systemaccording to claim 5 comprising a cable for the transmission of datafrom the imaging device of the apparatus.
 9. The system according toclaim 5 further comprising pressure control equipment which sealsagainst an exterior surface of the tool fluid conduit.
 10. The systemaccording to claim 5 further comprising a drive mechanism for pushingand/or pulling the tool fluid conduit into and out of the fluid conduitthrough the pressure control equipment.
 11. The system according toclaim 5 further comprising a blowout preventer.
 12. The system accordingto claim 11 wherein the blowout preventer comprises a shear and sealblowout preventer.
 13. The system according to claim 5 wherein in use,the system defines a fluid circulation path between an annulus definedbetween the tool fluid conduit and the fluid conduit of the hydrocarbonexploration or production installation; the flow direction arrangement,and the flow bore defined by the tool fluid conduit.
 14. A method ofinspecting the interior of a fluid conduit in a hydrocarbon explorationor production installation, the method comprising: providing aninspection apparatus in the fluid conduit to be inspected, the apparatuscomprising: a body coupled to a tool fluid conduit defining a flow bore;an imaging device carried by the body; and a flow direction arrangementdisposed between an exterior of the body and the flow bore; circulatingfluid between an annulus between an interior wail of the fluid conduitand the tool fluid conduit and the flow bore, through a fluidcirculation path defined by the flow direction arrangement; deployingthe apparatus along the fluid conduit by a thrust on the apparatusresulting from the circulation of fluid between the annulus and the flowbore through the fluid circulation path; and imaging the fluid conduitusing the imaging device to acquire imaging data.
 15. The methodaccording to claim 14 further comprising at least one of storing,analysing or displaying the imaging data.
 16. The method according toclaim 14 wherein at least one of deploying the apparatus or imaging thefluid conduit are performed in the presence of production fluids in thefluid conduit.
 17. The method according to claim 14 wherein at least oneof deploying the apparatus and/or imaging the fluid conduit areperformed while the hydrocarbon exploration or production installationis producing fluids.
 18. The method according to claim 14 wherein thefluid conduit comprises a flexible riser.
 19. The method according toclaim 18 comprising inspecting the interior of a flexible riser to alocation at which it is coupled to a subsea isolation valve.
 20. Themethod according to claim 14 comprising inspecting the riser side of asubsea isolation valve.
 21. A method of placing a treatment material atan interior of a fluid conduit in a hydrocarbon exploration orproduction installation, the method comprising: providing a materialplacement apparatus in the fluid conduit, the apparatus comprising: abody coupled to a tool fluid conduit defining a flow bore; an imagingdevice carried by the body; and a flow direction arrangement disposedbetween an exterior of the body and the flow bore; circulating fluidbetween an annulus between an interior wall of the fluid conduit and thetool fluid conduit and the flow bore, through a fluid circulation pathdefined by the flow direction arrangement; deploying the apparatus alongthe fluid conduit to a location displaced from the entry point to thefluid conduit, by a thrust on the apparatus resulting from thecirculation of fluid between the annulus and the flow bore through thefluid circulation path; placing a treatment material at the displacedlocation; and imaging the interior of the fluid conduit using theimaging device to acquire imaging data.
 22. The method according toclaim 21 further comprising at least one of storing, analysing ordisplaying the imaging data.
 23. The method according to claim 21wherein the displaced location is the location of a blockage, and thetreatment fluid comprises a blockage removal treatment fluid.
 24. Themethod according to claim 23 further comprising monitoring the effect ofthe treatment fluid on the blockage using the imaging device to acquireimaging data.
 25. The method according to claim 23 further comprisingadvancing the apparatus towards the blockage for further fluidtreatment.
 26. The method according to claim 21 wherein the displacedlocation is the location of a hydrate deposit in the fluid conduit, andthe method comprises removing at least a part of the hydrate deposit.27. The method according to claim 26, further comprising advancing theapparatus towards the hydrate deposit for further fluid treatment. 28.The method according to claim 21 wherein the displaced location is thelocation of a leak in the fluid conduit, and the method comprisesplacing a sealant at the displaced location.
 29. The method according toclaim 28 further comprising monitoring the effect of the sealant on theleak using the imaging device to acquire imaging data.